1. Technical Field
The present disclosure generally relates to a channel detection method and, more particularly, to a channel detection method for an echo canceller and a system using the channel detection method.
2. Description of Related Art
In a cable communication system, channel detection helps the user to determine whether a channel is open, short, impedance mismatched or normal. If there is any problem of connection, service providers or users may use channel detection to confirm whether there is any problem in the channel to clarify if the problem of connection is attributed to the channel itself (for example, the cable) and/or to point out the part of the channel where the problem takes place.
Conventionally, a pseudo-noise sequence (PN-sequence) is transmitted with auto-correlation to probe the channel conditions by determining the reflected signal in the channel and whether there is impedance mismatch in the channel.
Generally, in a cable communication system, additional hardware implementation is required for the calculation of auto-correlation. Moreover, with auto-correlation, each process only obtains one point in the reflected signal. Conventionally, it requires additional hardware implementation and longer testing time to realize channel detection by auto-correlation of a pseudo-noise sequence. However, if the communication devices (such as transceivers) at both ends of a channel perform channel detection at the same time, different pseudo-noise sequences are required to prevent cross-talk and to save time. In other words, additional hardware implementations are required for both communication devices so that the communication devices are provided with different pseudo-noise sequences. Such additional cost and testing time are not welcome to both the service providers and the users.